We have investigated the conformation control of a foldamer switch by light. An aromatic oligoamide sequence composed of a light responsive diazaanthracene-based aromatic -sheet flanked by two variable diameter helical segments was prepared. Structural investigations revealed that such oligomers adopt two distinct conformations: a canonical symmetrical conformation with the two helices stacked above and below the sheet, and an unanticipated unsymmetrical conformation in which one helix has flipped to directly stack with the first helix. Photo-irradiation of the foldamer led to the quantitative, and thermally reversible, formation of a single photo-product resulting from the [4+4] cycloaddition of two diazaanthracenes within the aromatic -sheet. NMR and crystallographic studies revealed a parallel (i.e. head-to-head) arrangement of the diazaanthracene photoproduct and a complete conversion to a symmetrical conformation requiring a rearrangement of all unsymmetrical conformers. These results highlight the potential of foldamers with structures more complex that isolated helices for the design of photo-switches showing nontrivial nanometer scale shape changes.

https://hal.archives-ouvertes.fr/hal-02322262/document

Light-Controlled Conformational Switch of an Aromatic Oligoamide Foldamer.

Revealing the interface-rectifying functions of a Li-cyanonaphthalene prelithiation system for SiO electrode

Ever since it was discovered and used widely in the synthesis of different organic compounds, quinoline became an interesting framework among chemists and pharmacists due to its unique properties. There are many familiar named reactions developed for the synthesis of quinoline based structures, among which the Friedlander reaction plays an important role. This method involves the condensation between 2-aminobenzaldehydes and a ketone. By developing the Friedlander synthesis, different types of heterocycles have been prepared in addition to the quinolines. In this chapter, the focus is on the applicability of the Friedlander reaction to the synthesis of various types of heterocyclic compounds.

The Friedländer reaction: A powerful strategy for the synthesis of heterocycles

We demonstrate a new refuelable lithium cell using lithium solvated electron solution (Li-SES) as anolyte and iodine solutions as catholyte. This cell shows a high OCV (~3 V). Unlike conventional rechargeable Li batteries, this kind of cell can be re-fueled in several minutes by replacing the spent liquids. We also show for the first time, that Li-SES/I2 cells which operate at room temperature, can be prepared in a fully discharged state (~0 V OCV) for safe handling, transportation and storage. Li-SES and iodine are then electrochemically generated during charge as is confirmed by UV-VIS and a qualitative test. We have also conducted proof-of-concept tests for an “indirect lithium-air” cell in which iodine is reduced at the cathode and subsequently is catalytically re-oxidized by oxygen dissolved in the catholyte.

/pdf/a-room-temperature-refuelable-lithium-iodine-and-air-battery-bvuktdy28u.pdf

A room-temperature refuelable lithium, iodine and air battery.

A route to the synthesis of novel 5,7-diazapentacenes and some preliminary studies on their properties is reported. A single crystal X-ray diffraction study of the dihexyl derivative showed it had formed a dimer during the analysis. The materials possess lower lying frontier orbitals than pentacene and may have potential applications in organic electronic devices. This synthetic method may be applicable to the synthesis of other azaacenes.

Synthesis and Electronic Properties of Novel 5,7-Diazapentacene Derivatives.

A route to compounds with a 5,7-diazapentacene skeleton has been established involving a Friedlander reaction. A diaminodiketone 8 has been made by a novel method and reacted with cyclohexanone to prepare an octa-hydro-5,7-diazapentacene 7a and with tetralone to produce a dibenzotetrahydro-5,7-diazapentacene 7b. Reaction of the diaminodiketone with a diarylethanone followed by oxidation gave a tetrabenzo-5,7-diazapentacene 18b. Compound 7b undergoes solid-state dimerization during single-crystal X-ray analysis. These materials possess lower frontier orbitals than pentacene and show strong absorption and fluorescence which is affected by the presence of acid. In particular 18b shows a remarkable colour change in solution upon addition of acid. These results suggest that suitably functionalised 5,7-diazapentacenes could be promising candidates for optoelectronic applications.

A Friedländer route to 5,7-Diazapentacenes

Synthesis and assessment of new cyclopenta-2,4-dienone derivatives for energy storage applications

This study aimed at developing a knitted fabric using conductive staple spun yarn composed of polypyrrole coated cotton fibers and characterizing its thermal, optical and electrical properties, hyd...

Development of functional knitted fabrics using yarn composed of polypyrrole coated cotton fibers

The authors report on conductivity studies carried out on lithium solvated electron solutions (LiSES) prepared using two types of polyaromatic hydrocarbons (PAH), namely 1,3,5-triphenylbenzene and corannulene, as electron receptors. The solid PAHs were first dissolved in tetrahydrofuran (THF) to form a solution. Metallic lithium was then dissolved into these PAH/THF solutions to yield either blue or greenish blue solutions, colors which are indicative of the presence of solvated electrons. Conductivity measurements at ambient temperature carried out on 1,3,5-triphenylbenzene-based LiSES, denoted by LixTPB(THF)24.7 (x = 1, 2, 3, 4), showed an increase of conductivity with increase of Li:PAH ratio from x = 1 to 2. However, the conductivity gradually decreased upon further increasing the ratio. Indeed the conductivity of LixTPB(THF)24.7 for x = 4 is even lower than for x = 1. Such behavior is similar to that of the previously reported LiSES prepared from biphenyl and naphthalene. Conductivity versus temperature measurements on corannulene-based LiSES, denoted by LixCor(THF)247 (x = 1, 2, 3, 4, 5), showed linear relationships with negative slopes, indicating a metallic behavior similar to biphenyl and naphthalene-based LiSES.

Andrey V. Lunchev

Papers

A Friedländer route to 5,7-Diazapentacenes

Synthesis and Electronic Properties of Novel 5,7-Diazapentacene Derivatives.

Synthesis and assessment of new cyclopenta-2,4-dienone derivatives for energy storage applications

Development of functional knitted fabrics using yarn composed of polypyrrole coated cotton fibers

1,3,5-Triphenylbenzene and Corannulene as Electron Receptors for Lithium Solvated Electron Solutions.